The C. elegans mechanosensory circuit serves as an ideal model to gain a comprehensive understanding of how and where plasticity occurs during learning and memory in an intact in vivo system. These remain fundamental questions in neuroscience regardless of the system. The C. elegans mechanosensory circuit has been shown to undergo habituation, a simple form of non-associative learning and memory. Habituation is defined as a diminished response to a given stimulus after repeated stimulations. Studying habituation is useful because of its simplicity and because it represents a ubiquitous form of learning. Both behavioral assays and new and established in vivo imaging techniques will be used to gain information about the cellular mechanisms underlying touch habituation. Together, these experiments will address key unanswered questions regarding the molecular mechanisms of neural plasticity in C. elegans, and are likely to provide insight into parallel processes in vertebrates. In addition, understanding the mechanisms behind this plasticity is important and relevant for changes that occur in drug addiction and withdrawal.